Manufacture of commutators



2' Sheets-Sheet 1 EEEEEWM Jul 10, 1928.

v R. G. JONES MANUFACTURE OF COMMUTATORS Filed Sept. 18, 1924 Plunger of fiydmu/ic. Press Patented July 10,1928.

UNITED STATES 1,676,442- PATENT OFFICE.

RUSSELL G. JONES, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, 'I'O DELCO-REMY CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

MANUFACTURE OF COMMU TATORS.

Application filed September 18, 1924. Serial No. 738,549.

This invention relates to-com1nutators for dynamo electric machines and particularly to the type of comnfutator which includes an annulus of metal segments having tangs 6 and spaced by insulating segments, insulating rings adjacent the ends of the annulus of segments, metal rings bearing against'the insulating rings and clamping the tangs of the segments between them, and means such as a tubular sleeve extending through the annulus for permanently maintaining the clamping rings in position.

One object of the present invention is to simplify the manufacture of commutators of this type. One method employed heretofore is disclosed in the patent to O. F. lonklin, N 0. 1,503,484, patented August 5, 1924, which specifies placlng insulating varnish upon theends of the annulus of metal segments before the insulating rings are assembled, par

tially crimping the ends of the center sleeve or core against the clamping rings, heating the entire commutator to a ten'iperature and for a time suflicient to cause the varnish to expand and fill the crevices between the parts of the annulus, completing the crimping operation while the commutator is still hot, and then baking the commutator to dry the varnish. More particularly, it is a further object of the presentv invention to provide certain improvements in the method of manufacturing commutators as described in the Conklin patent, said improvements tending to minimize the loosening of the commutator segments. I

The objects of the present invention are accomplished by using insulating rings which will soften under heat, forcing mctrl .clamping rings, which have been heated to a temperature sufficient to soften the insulat-- ing rings, against the insulating rings with pressure suflicient to cause the insulating rings to be pressed into the surface irregularities of the segments and to cause the tangs of the segments to be bent so that the pressure applied initially to the tangs will be substantially equalized, and in securing the clamping rings in clamping position while the clamping rings are still at a. higher temperature than the segments and while maintaining the pressure initially applied between the clamping rings and segments.

A further object of'the present invention is to provide apparatus by which this method may be practiced.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the pres ent invention is clearly shown.

In the "drawings:

Fig. 1 1s an end view of an assembled an nulus of metallic and insulating segments;

Fig. 2 is a sectional view on line 2--2 c5- of Fig. 1;

Fig. 3 is an end view of a commutator sleeve integral with one of the segment clamping rings;

Fig. 4 is asectional view on the line 4-4 of. Fig. 3;

Fig. 5 is an end view of the other segment clamping ring;

Fig. (i is a secticmal view on of Fig. 5; and

Figs. 7, 8 and 9 are fragmentary views partly in section showing apparatus in various stages of operation for carrying out the method described hereinafter.

Referring to the drawings, 20 designates an annulus of metallic segments 21 spaced by non-conducting segments 22. These segments are assembled within a metallic ring 23 which temporarily supports the annulus or segments. The ring 23 is shown, for sake of simplicity, as a solid ring but may be made in two or more parts secured together by clamping screws, such construction being well known to those skilled in the art.

The segments are each provided with a dove-tail portion 24 so that the annulus will provide two annular V-shaped grooves 25. These grooves are lined with non-cow ducting V-shaped lining rings 26. These rings are made of non-conducting material 95 which preferably includes mica and a substance such as shellac or varnish, so that the rings will soften under the action of heat.

For clamping the annulus permanently together there are provided a central core 27 1 0 andtwo clamping rings 28 and 29. Ring 28 is shown integral with the sleeve 27, however it will be apparent that the invention could be applied to a structure within both clamping rings or separated from the cen- 5 tral sleeve.

The clamping rings and sleeve are. first heated to a temperature of about 900 F. in a suitable furnace, and. are then removed and promptly assembled within the annulus as 110 the line 6-6 pressedwithin the apparatus which perma-.

nently secures the central core 27 to the clamping-ring 29. This apparatus comprises two clampingelements 30 and 31, which are movable, the one relative to the other. The clam ing element 30 may be secured to a suita le stationary support and the element- 31 may rest upon the plunger 32 or other movable member actuated by hydraulic press, or vice versa he. clamping member 30 includes a pressure ring portion adapted to engage the clamping ring 29. and a stakin or flaring portion 34 adapted to engage t e end of the sleeve 27 and to flare the same outwardly against the ring 29 as shown in l ig. 9. The pressure ring 33 is normally located in advance of the flaring portion 34 so that the V-rin 29 is held firmly in clamping engagement with the annulus before the flaring operation begins. The clamping member 30 includes a support 35.carrying an annular chamber 36, a piston 37 and a pilot member 40 which provides the flaring or staking portion 34. The pressure ring 33 is provided by a block 41 attached by screws 42 to a cylinder 43 which receives thev piston 37, and which is provided with an opening throngh'which the shank 38 extends. Separation of the cylinder and piston is prevented by an annular boss 44 of the cylinder 43 which engages the uppersurface of the pilot member 40 which extends around the shank 38.

. The space between the piston '37 and the in terior cylinder 43 provides a liquid chamber 45. Chambers 36 and 45 are connected by a relatively restricted passage 46 provided at its upper end with a valve seat portion 47 adapted to be engaged by a needle valve having a screw-threaded shank 49 engaging a bushing 50 which is screwed into the wall of the chamber 36. The upper end of the shank 49 is attached to an operating handle 51. The cylinder 43 is maintained normally with respect to'the piston 37 as shown in Fig. 7 by a plurality of springs 52 located between the walls of chamber 36 and cylinder 43. The springs 52 are retained in position by studs 53.

The operation of the apparatus shown in Figs. 7 to 9 inclusive is as follows:

The cylinder chamber 45 and passage 46 contain oil or other suitable pressure transmittin'g fluid and the valve 48 is closed upon its seat 47. The hydraulic press is operated to cause the plunger to move upwardly to causet-he clamping member 31 to approach the clamping member 30. As shown in Fig. 8, the pressure ring 33 engages the V-ring 29 before the flaringportion 34 engages the upper end of the sleeve- 27. The pressure exerted upon the V-rings must be sufficient to squeeze the mica insulating rings firmly and to draw all ofthe copper segments toward the'central sleeve. The heat of the clamping opened, as, shown in Fig. 9,'to permit a part of theliquid within the chamber 45 to flow upwardly through the passage 46 and into the chamber 36. This operation will permit movement of the clamping ring portion 33 relative to the flaring portion 34. The movement of the fluid through the passage 36 is relatively retarded so that 'there will be a gradual decrease of clamping pressure upon' the ring 29 and, at the same time, a gradual increase of pressure b etween'the flaring portion 34- and the upper end of the sleeve 27. When the flaring operation is completed, as

llll

shown in Fig. 9, substantially all of the pres sure exerted by the ,hydraulic press is localized between the flaring surface 34 and the flared-out edge of the central sleeve 27, and

.substantially all of the pressure exerted by the press is relieved from the ring engaging surface 33. As shownin Fig. 9, the flared edge of the sleeve engages the chamt'ered surface of the ring 29.

To restore the swedging press to the position shown in Fig. 7, the hydraulic press plunger is caused to move downwardly'in order that the finished commutator may recede from the clamping member 30. The springs 52 will bepermitted to expand to restore the normal relative positions of the clamping portions 33 and 34. Some of the oil in the chamber 36 will flow downwardly to fill the passage 46 and the chamber 45. The valve 48 is closed and the completed commutator and ring 23 are removed from the swedging press. The ring 23 is then removed from the completed commutator.

One of the principal advantages of the method included in the present invention is that clamping pressure is maintained upon the V-rings substantially throughout the entire flaring or swedging operation to form upon the end of the central sleeve. Atno time is there substantial release 0t pressure between the clamping rings and the dovetailed portions of the segments. Therefore from the time the rings are first clamped against the dove-tailed portions until the sleeve flaring operation is completed, there is no substantial easing up of pressure on the segments, therefore very little likelihood that any of the segments can become at all loose before the flaring of the sleeve is completed. In other words, the clamping sleeves are initially located inthe correct clamping position and are clamped together with such force as to cause the dove-tails of the segments to be distorted somewhat in order to clamp securely all of the dovetail portions regardless of slight variations in dimensions. The pressure between the flaring surface 34 and the end of the sleeve 27 is applied and this pressure gradually increases while the pressure against the-clamping rings dccreases so that there is little danger of the clamping rings backing away from the segments. There is a. transfer of pressure from the ring engaging surface 33 to the sleeve flaring surface 34. Therefore the pressure maintained by the press need not exceed that which is required for the sleeve flaring operation.

A further advantage of the invention is to be found in the fact that after the assembly of the annulus and clamping rings has I been made there is but one press operation to be performed. In methods of'commutator manufacture heretofore employed, such as disclosed in the Conklin Patent No. 1,503,484, a commutator is baked after an initial press operation for securing the clamping rings, and then a final press operation is performed. It is apparent that the present invention simplifies the method of commutator manufacture by reason of the fact that the clamping rings and central tube are heated prior to their assembly with the annulus of segments. There is suflicient heat in the V-rings to cause the insulating rings 26 to soften .and be pressed into the surface irregularities of the V-rings and segments.

The metallic segments are usually made of copper and the clamping rings and central sleeve of steel. Heating of the segments and rings in the baking operation referred to as a part of an old process is disadvantageous in that the copper, having greater coefficient of expansion than the steel rings would tend to loosen on cooling from the steel rings. In the present invention the steel sleeve and rings are pressed on while at a much higher temperature than the copper segments. The rings and sleeve contract on cooling and cause the segments to be more firmly clamped.

The staking pressure is preferably greater than the V-ring clamping pressure. If, for example, 8 tons per square inch is suitable for ring clamping pressure, about 12 tons per square inch is'suitable for staking pressure.

The temperatures of the sleeve and rings at the time the press operation begins is preferably above 600 F. There may be considerable variation in temperature above this amount.

While a hydraulic press is indicated on the drawing, an air press may be used advantageously since air is more elastic and will not transfer extreme ressures sudden: ly in case of the sticking o in the pressure regulator.

The radius of curvature of the staking surface 34'will depend on the size of commutator. A radius of inch to inch has been found satisfactory for a two inch commutator sleeve.

This invention is not limited to the manufacture of comn'ultators having one of the V -rings integral with the, sleeve. Both V- rings may be separate from the sleeve and and the sleeve may be staked at both ends in one operation by a press having two clamping elements 30 or hydraulic pressure pads operatin upon both ends of the commutetor. It has been found desirable to form one of the elements 34 to a radius of curvature different from the element 34 operating upon the opposite end of the commutator. For example, for a 2 inch sleeve the radius of curvature of element 34 of the upper hydraulic pad may be inch, and that. of the lower inch. The surface 34 of small radius will force the sleeve upon the surface 34 of larger radius until the sleeve abuts a definite stop whereupon both staking sur-,

faces 34 begin flarin the ends of the sleeve.

While the form of embodiment of the invention as herein disclosed, constitutes a. preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows:-

1. The method of making a commutator which comprises assembling an annulus of metal segments having anchoringtangs and spaced b insulation, placing against the ends of the tangs rings of insulating material adapted to soften under heat, forcing metal clamping rings, which have been heated to a temperature sufficient to soften the insulatin rings, against said insulating rings with pressure suflic-ient to cause the insulating rings to be pressed into the surface a spring or valve irregularities of the segments and to cause the tangs to be bent so that the pressure applied to the tangs will be substantially equalized, and in securing the clamping rings in clamping relation while the clamping rin'gs'ale still at a higher temperature than the segments. i

2. The method according to claim 1, in which the metal clampin rings are secured in clamping position whi e maintaining the pressureinitially applied between the clamping rings and segments.

3. The method of making a commutator which comprises assembling an annulus of metal segments having anchoring tangs and spaced by insulation, placing against the ends of the tangs rings of insulating material adapted to soften under heat, providing metal clamping rings adapted to clamp the tangs'and a central, metal sleeve for securing the rings in clamping position, at least one of the rin s being separate from the sleeve, heating t 1e clamping rings and sleeve to a temperature sufficient to soften the insulating rings, assembling said clamping rings and sleeve with the segments and insulating rings, the clamping rings being placed against the insulating rings and the sleeve located centrally of the assembly, forcing the clamping rings while thus heated against the insulating rings with pressure sufiicient to cause the insulating rings to be pressed into the surface irregularities of the segments and to cause the tangs to be bent so that'the pressure applied to the tangs will be substantially equalized, and in swedging the sleeve against the separate ring while the rings and sleeve are still at a higher temperature than the segments.

4. The method accordin to claim 1, in which the sleeve is swedged while maintaining the pressure initially applied between i the clamping rings and segments.

5. The method of making a commutator which comprises assembling an annulus of metal segments having anchoring tangs and spaced b insulation, placing against the ends of tiie tangs rings of insulating material, forcing metal clamping rings against the insulating rings with pressure sufiicient to force the insulating rings into the surface irregularities of the segments and to cause the tangs to be bent so as to tend to equalize the pressure applied to the tangs,

and then securing the clamping rings in clamping position by joining them by apart extending through the commutator annulus while maintaining the clamping pressure initially applied between clamping rings and segments.

6. The method of making a commutator which comprises assembling an annulus of metal segments having anchoring tangs and spaced by insulation, placing against the ends of t e tangs rings of insulating matesleeve located centrally of the assembly, forcing the clamping rings against the insulat-' ing rings wit insulating rings to be pressed Into the surpressure suflicient to cause the face irregularities of the segments and to cause the tangs to be bent so as to tend to equalize the pressure applied to the tangs, and in swedging the sleeve against the separate ring While maintaining the pressure.

initially applied between the clamping rings and segments.

In testimony whereof hereto aflix my signature.

Y RUSSELL G. JONES. 

